You don't have to be sorry for me not fully understanding the airline (no caps) industry. People/companies do all sorts of shit I don't understand. That's kinda my point.
That sounds like more of the blah blah weak justification for failure that I was getting at. (OMG! The ocean is big? No shit dude. Seriously, GTFO with that.) We can land R2D2 on an asteroid and hit flying bullets with a freaking laser but finding a plane crash in the water is just unpossible. I'm an idiot for even suggesting such a thing.
Dumb comparison. Spaceflight dynamics is fairly simple because there isn't much in space to mess up sensor data, the distances involved means that searches encompass massive areas at once, and the majority of spaceflight mechanics can be calculated by a college junior and a graphing calculator.
Secondly, we tend to know exactly where things are because we have entire companies dedicated to tracking a single object in space.
Also our rocket/missile.projectile interception systems aren't as good as you think. They're good, but we still rely on the "fill the sky with as much shit as possible and hope that something intercepts the projectile" method.
There is a reason submarines are relevant in modern warfare. The ocean is so damn big and there is so much shit between you and a sensor, that if you don't want to be found, its really really hard to find you. And even if you don't care, it's still hard to find because there is a lot of area to search, and searches can only focus on small areas at a time.
Hell in Air France, we know exactly where it went down, and it still took 5 days to get at wreckage.